Henry Petroski’s 1990 The Pencil was one of the early books in a now fairly common genre, which takes ordinary objects (salt, cod, etc) and examines them in light of their history, physical attributes, and cultural impact. Petroski showed a deft hand making the ordinary pencil an object of interest. For instance, why are most pencils yellow? At one time yellow was considered elegant and associated with China, from which some of the best graphite came. Since then he has published sixteen additional books, some on engineering and society, and some along the lines of The Pencil. His book The Evolution of Useful Things explains how things like paperclips and forks did not just appear one day, but were the result of careful research to solve specific problems.
In this book he looks back on a lifetime as a civil engineer, primarily as a professor at Duke University, and explains the technical, social, political, and financial forces that affect engineering projects. The chapter on road construction was particularly good, starting with the history of various paving methods and moving on to the options available today, primarily the choice between concrete and asphalt. Concrete is much longer lasting, and if properly applied can last for decades, but asphalt is faster and easier to apply and thus cheaper, although its lifetime maintenance costs will be approximately three times its initial cost. Petroski also explains the history and eventual standardization of lane markings, causing me to actually pay attention to them for the first time.
And who knew that stoplights had such a long and complicated history? It was not until 1930 that the current order of lights, with red on top, then yellow, then green became the standard, which was a great help to the 10 per cent of male drivers who are color-blind and see both red and green as shades of gray. Even so, one Irish-American community in Syracuse, New York insisted that green should be the top color, an homage to their former homeland, and it was not until the 1960s that their stoplights followed the standard pattern.
The book has a number of interesting facts, such as:
- A million households had been established in the United States by 1800, and another million by 1825, a rate of one hundred a day.
- In 1900, city traffic was primarily horse-drawn. In New York City at the time there were 130,000 horses, each of which produced an average of about twenty-five pounds of manure and a quart of urine daily.
- Stop signs initially elicited such strong feelings of opposition that in 1922 they were ruled illegal by courts in Illinois because they were “a violation of the right of individuals to cross streets.”
- According to the Texas A&M Transportation Institute, traffic congestion alone costs the country $121 billion annually in lost time, which amounts to more than $800 per driver. For truckers, the cost in wasted time and diesel fuel consumption is about $27 billion annually.
- In the United States, each day on average 650 water mains fail and seven billion gallons of water are lost through leaks, resulting in about 16 percent of clean drinking water being wasted.
- At the beginning of interstate construction in 1956, the Bureau of Public Roads, which was overseeing the program, had projected the final cost to be $27.5 billion; after the first five years of construction the revised estimated cost was $41 billion. Some of the 50 percent increase was attributed to inflation, but an estimated 10 to 20 percent of it was blamed on graft amounting to at least $100,000 per mile of highway built.
Only part of the book focuses on how engineers analyze and solve problems, the rest looks at the intersection of engineering and society. There is an instructive chapter on how the best-laid plans for replacing the San Francisco-Oakland Bay Bridge after it was damaged in the 1989 Loma Prieta earthquake went awry. Initial estimates were that it would cost $200 million to retrofit the bridge and in excess of $1 billion to replace it. And then politics got involved, along with corruption, incompetence, and frequent changes to the designs, which “led state politicians to call for a criminal investigation of Caltrans by the California Highway Patrol. According to one report, Caltrans was under investigation for ‘knowingly accepting substandard work at taxpayer expense, and retaliating against those who sought to bring problems to light.’ ” By the time the new bridge opened in 2013 its price tag had risen to $6.4 billion, plus another $400 million to remove the old bridge. People of California, your tax dollars at work….
Sometimes the book meanders away from its premise as Petroski takes time to explain his personal experiences with things like the storm drains in front of his house or problems with repairs to his driveway. Although he tries to tie these incidents back to the larger issues discussed in the book, it doesn’t really work. Nevertheless I learned quite a bit, and in particular that only bad things happen when politicians start getting involved in engineering decisions.